Last year on my MAC I was able to export from my AFX timeline straight to AVI. Now the option is no longer available. All that has changed is me cloning over my previous machine onto a faster newer MAC.
How can I export to AVI without going through Quicktime Player (because it's not yielding the results I want). I have to export my animation from AFX in order to play it on a specific machine for a client.
Unless you're using a version of AE in which Adobe removed AVI support, which I seriously doubt, it's probably that you didn't install any AVI codecs when you "clon[ed] over my previous machine onto a faster newer MAC". Try downloading and installing a codec that can be wrapped in an AVI file.
I don't know off-hand where to download the codec you want, but I'm sure a Google search will offer many options. Perhaps you have one installed, but it's damaged and needs to be re-installed. It's not really an AE issue ... even though AE supports the formats, you would not be able to render to the FLV or WMV formats either if corresponding codecs weren't installed on your machine.